We are engaged in a coordinated program for the study of gene regulation in experimental mammals, especially inbred strains of mice. Work is proceeding in 8 areas: (1) Molecular Aspects of Gene Regulation, (2) Physiological Regulation of Lysosomal Glycosidases, (3) Mup Regulation, (4) Gene Regulation in Early Mammalian Development, (5) Membranes, (6) Gene Mapping, (7) Development of New Genetic Stock, (8) DNA Cloning.